Tell Us Your Top 10 Sci-Fi Movies

Our crazy, argument-inducing, week-long project of asking people to nominate all things best in science fiction and fantasy continues. Yesterday we asked you to nominate your favoritefantasy novels. Today we're embarking on a more contentious category. We seek nominations for the top science fiction movies.

"I'm sorry, Dave. I'm afraid GeekDad can't do that."

Yes, Hal. We can do that.

To remind you of the rules. Well, not rules. But the question in our collective minds, perhaps, is this: What the heck is the difference between science fiction and fantasy? Our quick definitions are__:__

Sci-fi: Future/space/technology as primary theme.

Fantasy: Supernatural/magic/mythical as primary theme.

Obviously there will be cross-over and overlap. Some sci-fi might have magic, or fantasy might have technology; some worlds that appear to be primarily based on swords-and-scorcery aren't necessarily purely "medieval-looking." Likewise, in Star Wars, there's "the Force" – more of a magical concept than anything else. In fact, many argue that Star Wars actually is more of a fantasy film, or even more of a Western, than it is pure SF. But to avoid hair-splitting fights, we're going to call the Star Wars universe science fiction. So there.

If you disagree with someone else's classification during the nomination period, we invite you to comment. And, to make this easier, we are looking for single movies, not series. You can nominate an entire series, but please list each film individually. So if you like the Star Trek movies, don't just say Star Trek. You have to choose one of the many Trek film titles and flavors (original Kirk taste, The Next Generation recipe, new prequel reboot sauce). Be specific.

To leap into the fray, here is my list of ten science fiction movies. These are films that I love, that I cherish, that were important to me or to the history of the genre for various reasons. There are literally hundreds of other movies that could be worthy. We know you will have your own, so add them in the comments for this post, and we'll include them for next week's voting.

Metropolis – Directed by Fritz Lang, this 1927 black and white classic set the tone for the genre: big budget, fancy special effects and set designs, and a scary robotic future.

Star Wars: Episode IV–A New Hope – It's hard not to make a list without including this seminal, 1977 blockbuster that brought sci-fi to the masses for the first time.

Alien – Maybe the first successful horror/sci-fi thriller, in Ridley Scott's 1979 movie, the visual looks and doom-and-gloom atmosphere set the standard for realistic futuristic design.

2001: A Space Odyssey (1968)– A yawner for some, a mind-bender for others, it's hard to ignore the influence of this spellbinding head trip that ushered in a new level of special effects and visual impact.

Blade Runner – Another Ridley Scott masterpiece, this 1982 futuristic noir/existential mash-up, based on the Philip K. Dick novel, had us all thinking about artificial life and memories in a fresh way.

The Terminator –James Cameron's thriller about a cyborg assassin sent back in time to kill the mother of a future rebellion leader was groundbreaking in its use of action and wit.

The Day the Earth Stood Still – In 1951 there was less cynicism, perhaps: An alien comes to Earth, accompanied by a powerful robot, not to invade us, but to deliver a message to humanity that we have to stop our violent ways.

Forbidden Planet– Another triumph of design and special effects (can you see my bias here?), this 1956 sci-fi version of Shakespeare's The Tempest was the first film that set entirely on another planet.